U.S. patent number 4,734,603 [Application Number 06/870,470] was granted by the patent office on 1988-03-29 for motor control mounting.
This patent grant is currently assigned to Papst-Motoren GmbH & Co. KG. Invention is credited to Rolf Mueller, Georg F. Papst, Johann von der Heide.
United States Patent |
4,734,603 |
von der Heide , et
al. |
March 29, 1988 |
Motor control mounting
Abstract
To lessen mounting time and to optimize positioning of the Hall
generator, the Hall generator and control electronics influenced by
the generator so as to actuate a brushless dc motor are arranged on
a common substrate and are provided with a common protective
envelope whose dimensions are somewhat narrower than the
cross-section of the motor slot. This substrate is inserted in the
motor slot so that the Hall generator is located outside the slot
and in the effective magnetic field of the motor's permanent
magnet.
Inventors: |
von der Heide; Johann
(Schramberg, DE), Papst; Georg F. (St. Georgen,
DE), Mueller; Rolf (St. Georgen, DE) |
Assignee: |
Papst-Motoren GmbH & Co. KG
(Black Forest, DE)
|
Family
ID: |
6272341 |
Appl.
No.: |
06/870,470 |
Filed: |
June 4, 1986 |
Foreign Application Priority Data
Current U.S.
Class: |
310/72; 310/214;
310/68B |
Current CPC
Class: |
H02K
29/08 (20130101) |
Current International
Class: |
H02K
29/08 (20060101); H02K 29/06 (20060101); H02K
029/08 () |
Field of
Search: |
;310/67R,68B,69,72,214,DIG.6,71,254 |
References Cited
[Referenced By]
U.S. Patent Documents
|
|
|
4539499 |
September 1985 |
Punch et al. |
4549104 |
October 1985 |
Nimura et al. |
|
Foreign Patent Documents
Primary Examiner: Salce; Patrick R.
Assistant Examiner: Rebsch; D. L.
Attorney, Agent or Firm: Fitch, Even, Tabin &
Flannery
Claims
What is claimed is:
1. A brushless d.c. motor having a rotor with a magnetic field, a
stator, slots in the stator having a given width and cross section,
a winding system held in the cross section of the slots of the
stator, electronic controls controlling current in the winding
system and a Hall device detecting the position of the rotor and
providing a control signal for the electronic controls to regulate
the motor, the motor further comprising an elongated substrate
mounting both the Hall device and the associated electronic
controls; an envelope enclosing in common the substrate, the Hall
device, and the electronic controls, the width of the combined
envelope and substrate being less than the given width of the cross
section of the slots, the Hall device being mounted on the
elongated substrate adjacent one of its ends, and the combination
envelope with substrate, Hall device and electronic controls being
disposed within the cross-sectional area of one of the motor slots
and with the Hall device end extending outside the slot but within
the magnetic field of the rotor, whereby the Hall device is able to
provide an effective control signal substantially interference free
in response to the magnetic field of the rotor.
2. A motor in accordance with claim 1 further comprising power
leads to the motor being firmly connected to the control
electronics from the end of the elongated substrate opposite the
Hall device end, the connections being on the substrate within the
slot and within the enclosure of the envelope.
3. A motor in accordance with claim 1 further comprising a frame
for containing the combination substrate, Hall device, electronic
controls and envelope, and means physically connecting the frame to
the substrate.
4. A motor in accordance with claim 2 further comprising a frame
for containing the combination substrate, Hall device, electronic
controls, motor leads connections and envelope, and means
physically connecting the frame to the substrate.
Description
MOTOR CONTROL
The present invention concerns a brushless dc motor provided with
electronic controls influenced by a Hall generator.
Motors of this type are provided with a means of detecting the
position of the rotor, which takes the form of a Hall generator,
and they are also provided with electronic amplification to
generate the signal from the Hall device which is employed to
regulate rotor speed.
Hall generators are typically positioned where the rotary magnetic
field will generate a signal giving the least interference. The
electronic controls are normally arranged on a mounting board which
is in turn connected to the stator.
Mounting the above individual elements does not usually give rise
to further problems, but it is a time-consuming task, and
consequently any means of reducing assembly time will have a
considerable effect on the cost of motors of the aforesaid type.
The space envelope required for the mounting plate will also play
an important part, since this will generally be of critical concern
in the design of electronic motors.
Optimizing the location of the Hall device is a further problem in
this context.
If the Hall device is arranged too far outside the permanent magnet
field, the latter will exert too weak an effect, whereas a very
strong influence will be exerted by stray fields from the field
coil.
The arrangement of the main sensing surface of the Hall device in a
radial direction, which will generally be imposed by the dimensions
of the generator and the positioning of the mounting plate, will
tend to degrade the signal/noise ratio because the influence of the
permanent magnet field will then run parallel to the main sensing
surface of the Hall generator, thus inducing a very low Hall
voltage. In such cases, the stray field will be oriented more or
less vertically with respect to the main sensing surface of the
Hall generator; consequently, control signals will be subjected to
strong interference and will be of low amplitude.
Hence, the task of the present invention is to provide an
arrangement combining lower mounting costs and enhanced motor
control.
This problem is resolved in the present invention by arranging the
Hall generator and the motor control electronics which are under
the influence of the generator on a single substrate provided with
a common protective envelope whose external dimensions are somewhat
narrower than the motor slot cross-section, whereby the substrate
is inserted in the motor slot so that the Hall generator can be
positioned outside the slot but within the effective range of the
permanent magnet of the motor.
One advantage of this arrangement is that it provides internal
electric connections between the Hall generator and the electronics
of the control unit, thus obviating the need for further wiring,
apart from that required for the power supply and regulation of the
motor. The familiar bonding method is used for the internal wiring
which is, generally speaking, adequately protected by the
surrounding envelope.
This arrangement is merely inserted in the motor slot where it can
be retained in position by the elasticity of the potting material
itself or by other flexible means, without the need for other
mounting aids.
The main advantage of this arrangement is that it provides a
space-saving means of locating the Hall generator in the stator in
the upper part of the rotor housing of a motor provided with an
external rotor. In this area, the permanent magnet field is very
strong, whereas the stray field will be very weak, and the
arrangement is almost completely protected against outside
influences.
Furthermore, no additional space envelope is required to
accommodate the controls.
In a further development of the present invention, the supply leads
to the motor and regulation system are firmly connected and potted
together with the control unit.
In an other further development, the control unit is inserted in a
special frame adapted to the motor slot to which it is connected
with metal lugs.
The invention will now be elucidated with the help of the following
drawings, where:
FIG. 1 shows a control unit positioned in the motor slot
FIG. 2 shows a control unit provided with a frame and power supply
leads
FIG. 3 shows a motor control circuit
FIG. 1 shows a Hall generator 20 mounted on a substrate 10 and an
electronic amplifier 30 arranged separately. The Hall generator is
arranged on a chip of A3B5 compound and is connected to the
amplifier 30 by means of bonding wiring 21. The entire arrangement
is housed inside a plastic protective envelope 100.
If the Hall device is built up on a silicon chip, the Hall
generator and the amplifier can both be arranged on a single chip.
In this case, the bonding wiring can be omitted.
The supply and output leads from the amplifier are run in bonding
wiring 31 to the solder support points 41, to which can be
connected the power leads 40 from the power supply (not shown) and
from a capacitor as well, if needed.
The entire control unit 1 is inserted in a slot N in the winding W
of the motor M, in which it is potted in varnish, for example. The
Hall generator projects above the slot in this case.
The permanent magnet field F1 impinges perpendicularly on the Hall
generator 20 in its position at the mouth of the slot, whereas the
stray field at the end of the slot is oriented almost parallel to
the slot axis. In this way, the Hall generator produces a strong
signal, free of interference, thus obviating the need for high
level amplification. A particular advantage of this arrangement is
that it allows the use of a Hall generator of one-piece design
built up on a silicon chip, whereby the Hall voltage will be lower
than if an A3B5 chip were used.
This advantage which derives from the method of mounting the Hall
generator is particularly distinct if the control unit is mounted
in the upper part of the slot of a motor provided with an external
rotor. This position is only accessible over the stator stack. The
distinctive feature in this case is that the Hall generator is
protected as fully as possible from the effects of any outside
fields. Compared with traditional designs employing mounting
boards, the present invention not only allows considerable cost
savings, but also saves a great deal of space, which is of
particular importance in the design of motors in apparatus and
appliance applications.
FIG. 2 shows a substrate 1 soldered in a frame 2. This frame is
flexible and fits in the slot of the motor employed in this case.
This arrangement allows the same control unit 1 to be fitted to
various types of motor. The control unit is fastened to the frame 2
by means of metal lugs L1, L2, . . . L10.
The electric functions of the arrangement according to the present
invention is shown in FIG. 3. In this instance, the motor winding W
is driven by the driving amplifier 30 which is supplied with
control signals by the Hall generator 20. The power supply for this
arrangement is indicated at Vs and OV.
* * * * *